/Engine/Source/Runtime/Core/Public/Serialization/PackageWriter.h
Asynchronously create a CompactBinary Object message that replicates all of the package data from package save that is collected in memory and written at end of cook rather than being written to disk during package save. Used during MPCook to transfer this information from CookWorker to CookDirector. Called after CommitPackage, and only on CookWorkers.
[TFuture](API\Runtime\Core\Async\TFuture)< [FCbObject](API\Runtime\Core\Serialization\FCbObject) > WriteMPCookMessageForPackage ( [FName](API\Runtime\Core\UObject\FName) PackageName )